The present invention relates to a regeneration valve adapted for automatic activation of ion exchange resin in a water softener.
Raw water supply to cooling/heating apparatus such as boiler, water heater or cooler is usually carried out in combination with the water softener connected to said apparatus. The water softener functions to remove hardening component of various types (e.g., alkaline-earth metal ion such as Ca cation or Mg cation) contained in raw water in order to avoid scale deposition. Particularly, the water softener of automatic regeneration type (hereinafter referred to simply as water softener) using ion exchange resin of Na cation type to remove the hardening component from raw water has been widely used.
In the water softener of this type, the hardening component is substituted with Na cation of the ion exchange resin and thereby removed from raw water. A break through point is reached as substitution of the hardening component with Na cation is saturated, whereupon the hardening component begins to leak into water being softened. At this point, the ion exchange resin is brought into contact with saline solution (NaCl) to reverse the precedent reaction and thereby to regenerate a hardening component removing ability. More specifically, the hardening component having been adsorped on the ion exchange resin is eluted therefrom and Na cation is adsorpted on the ion exchange resin.
An example of the apparatus using the regeneration valve used for the regenerating process as has been described above is disclosed in U.S. Pat. No. 4,290,451.
Construction of this well known apparatus will be briefly described in reference with FIG. 19 in the accompanying drawings.
Referring to FIG. 19, reference numeral (151) designates a resin reservoir filled with ion exchange resin (161) connected to a regeneration valve (152) including a piston (162). The regeneration valve (152) is connected to a water passage (153) vertically extending within the resin reservoir (151) substantially axially downward to the vicinity of a bottom of said resin reservoir (151). The water passage (153) is provided at its lower end with a water inlet (154).
The regeneration valve (152) includes, in addition to an electric motor serving to actuate a passage switching mechanism, a controlling timer mechanism (155). The latter is adapted to set the regeneration valve (152) to a position for regenerating process when a predetermined time point or a predetermined amount of raw water has been reached.
The regeneration valve (152) further includes members as following: a raw water inlet (156) through which the resin reservoir (151) is supplied with raw water; a softened water outlet (157) to discharge the amount of softened water free from the hardening component; a saline solution pipe (159) adapted to pump up an amount of saline solution from the saline solution reservoir (158) during the regenerating process and, at the end of this process, to fill up an amount of raw water necessary for preparation of saline solution to be used in the next regenerating process; and a drainage port (160) adapted to drain the amount of saline solution and excessive raw water having been used for regeneration. These members are appropriately provided at positions adapted for respective passages switched one from another in the respective steps of process.
An air chuck (164) having its inlet (163) in the vicinity of the bottom of the saline solution reservoir (158) is connected to the distal end of the saline solution pipe (159). The air chuck (164) functions to open the passage defined by said saline solution pipe (159) so far as the inlet (163) is immersed in water. The air chuck (164) functions to close said passage as the surface of water lowers to a level of said inlet (163). In this way, the air chuck (164) prevents any amount of air from entering the-saline solution pipe (159).
Within the saline solution reservoir (158), common salt (139) for reactivation of the ion exchange resin (161) and there is provided a salt filter having fine meshes. Said salt filter functions to prevent grains of common salt (139) from falling onto the bottom of the saline solution reservoir (158).
In the water softener of this type, switching of the regeneration valve (152) is effectuated by the controlling timer mechanism (155). Specifically, the valve (152) is switched from the position for collection of softened water to the position for regeneration of the ion exchange resin (161) depending on a predetermined condition. More specifically, switching occurs when a predetermined time or a predetermined discharged amount of softened water is reached.
Once the regeneration valve (152) has been switched to the position for the regenerating process, the steps of this process are successively carried out. These steps include those of xe2x80x9cback washingxe2x80x9d, xe2x80x9cregeneration of saline solutionxe2x80x9d, xe2x80x9cexpelling saline solutionxe2x80x9d, xe2x80x9cwashingxe2x80x9d and xe2x80x9cwater injectingxe2x80x9d. As a result of these steps, the ion exchange resin (161) having its initial ability deteriorated now recovers it, allowing the valve (152) to recover the position for softened water collection.
Such regeneration valve (152) of the water softener usually comprises a piston (162) reciprocation of which causes increases in the number of steps included in the regenerating process to be increased to seven: first step of washing, first step of back washing, step of saline solution injecting, step of expelling saline solution, second step of back washing, second step of washing and step of water injecting.
The single piston (162) reciprocates across the passage associated with each step. In the steps of saline solution injecting/expelling out, forward stroke of the piston (162) causes saline solution to flow downward through the ion exchange resin layer. Then the amount of water having been reacted with the ion exchange resin is drained. In the step of back washing, backward stroke of the piston (162) causes raw water to flow upward through the ion exchange resin layer.
Consequently, most of saline solution flowing downward flows through the water inlet directly into said water duct (153) through the resin filter. This means that the ion exchange is limited to a central zone of the resin reservoir (151) and no regeneration occurs in the vicinity of a side wall of the resin reservoir (151).
In addition, the amount of water to be drained after completion of the reaction is drained through the ion exchange resin layer in the second step of back washing. However, this water flow is forced back by the amount of water flowing downward again in the second step of washing. While a certain amount of water is drained, a cycle in which these steps are repeated is too short to ensure the complete drainage after the step of expelling out. Actually, a considerable amount of water to be drained merely wanders within the ion exchange resin layer.
In view of these problems, it is a principal object of the present invention to provide a novel automatically regeneration valve in a water softener. This valve can automate the entire process of activating the ion exchange resin with saline solution so that said resin within a reservoir thereof may be uniformly regenerated.
The object set forth above is achieved, according to the present invention, by a water softener having components as following: a resin reservoir filled with ion exchange resin; a saline solution reservoir containing saline solution used to regenerate said ion exchange resin; and an automatic regeneration valve. To this automatic regeneration valve, a plurality of ducts are connected. Namely, a raw water duct supplying said resin reservoir with raw water; a softened water duct feeding the amount of water having been softened in said resin reservoir forward; a drained water duct draining the amount of water used to regenerate said ion exchange resin; and a saline solution duct for suction as well as injection from and to said saline solution reservoir. Said automatic regeneration valve may be switched at a predetermined switched to switch a step of softened water collection to successive steps of a process for ion exchange, resin regeneration. Said automatic regeneration valve comprises a switching valve, a control valve, water injection valve, a cam mechanism and a timer mechanism.
The switching valve may contain therein a plurality of switching pistons having their piston rods each extending vertically. According to this embodiment, the steps of the regenerating process successively take place as positions of these switching pistons are switched. In this way, the process of regeneration is reliably carried out with a relatively simplified construction. The cam mechanism may include a drainage valve actuating cam, a saline solution valve actuating cam and a regeneration control lever. Such construction enables the process of regeneration to be continuously carried out.
A regeneration control lever provided in the cam mechanism may be actuated by a timer mechanism. The timer mechanism may comprise a timer motor provided with a switching gear adapted to be switched between 50 Hz and 60 Hz. The timer motor of the timer mechanism may be provided with a conversion gear so that this conversion gear can be operated to switch a regeneration mode to a manual regeneration mode.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.